Magnetic tape apparatus

ABSTRACT

A magnetic tape apparatus is disclosed herein and comprises a drum, means for supporting and rotating the drum, at least one transducer extending past the surface of said drum adapted to rotate therewith in a given plane, and means for presenting tape to said drum with its longitudinal axis parallel to said plane. Means are also provided adjacent the transducer for venting air from the air cushion between the rotating drum and the tape at the region of the transducer to bring the tape closer to the face of the transducer and at least one groove formed on the face of the transducer is used for venting air from the cushion between the transducer and tape.

This invention relates to a tape apparatus and more particularly to amagnetic tape apparatus for recording and reproducing longitudinallydisposed record blocks or pages of parallel multiple tracks ofpredetermined length on the magnetic tape.

In copending application Ser. No. 45,215, filed June 4, 1979, now U.S.Pat. No. 4,285,016, assigned to the same assignee, there is shown anddescribed a tape apparatus for recording and reproducing longitudinallydisposed record blocks of parallel multiple tracks of predeterminedlength. The apparatus includes a rotating drum and means for presentingpredetermined lengths of tape to said drum. The rotating drum supportsthe tape on a self generating air bearing. Magnetic heads extend fromthe drum to rotate with the drum and cooperate with the tape to recordon and reproduce from the tape. The heads are movable longitudinally torecord a plurality of adjacent tracks. The length of the tracks dependsupon the amount of wrap of the tape about the drum and the spacing ofthe magnetic heads or transducers. The plurality of spaced tracks ofpredetermined length form longitudinally disposed record blocks orpages.

It is an object of the present invention to provide an improved magnetictape drive apparatus of the above character.

It is another object of the present invention to provide an apparatus inwhich the tape is maintained on the drum with predetermined tension incooperation with the self generating air bearing.

It is a further object of the present invention to provide a selfcompensating head guide assembly.

It is a further object of the present invention to provide aself-threading single reel magnetic tape drive apparatus.

It is a further object of the invention to provide a coaxial transformerassembly for transmitting signals from rotating heads to associatedapparatus.

These and other objects of the invention are achieved by a tape driveapparatus including a drum, means for rotating said drum, at least onetransducer extending from the surface of the drum and adapted to rotatetherewith, means for moving said transducer longitudinally along saiddrum, means for supplying tape to said drum including supply and take-upmotors adapted to drive supply and take-up reels, means for presentingsaid supply reel to a drive means driven by said supply motor, meansincluding torsion spring means for driving said take-up reel from saidtake-up motor to control the tension of the tape on said drum. Otherobjects are achieved by an improved rotary transformer, guide means forguiding the heads in longitudinal movement, and a single reel selfthreading arrangment.

The invention will be more clearly understood from the followingdescription with reference to the accompanying drawings in which:

FIG. 1 is an exploded view of tape apparatus in accordance with thepresent invention.

FIG. 2 is a plan view of the tape apparatus of the present invention.

FIG. 3 is a sectional view taken along the line 3--3 of FIG. 2.

FIG. 4 is a sectional view taken along the line 4--4 of FIG. 2.

FIG. 5 is a sectional view taken along the line 5--5 of FIG. 2.

FIG. 6 is a sectional view taken along the line 6--6 of FIG. 3.

FIG. 7 is a view taken along the line 7--7 of FIG. 2.

FIG. 8 is a front view of FIG. 7 showing the face of a magnetictransducer.

FIG. 9 is an enlarged view of FIG. 7.

FIG. 10 is an enlarged view taken along the line 10--10 of FIG. 8.

FIG. 11 is a block diagram of the take-up and supply motor control.

The magnetic tape drive apparatus is disposed in a housing whichincludes a U-shaped sheet metal portion having upstanding sides 11 and12 and bottom 13. The front panel 14 accommodates one end of theU-shaped housing portion while a rear panel 16 is suitably attached tothe back to form a box-like enclosure. A transparent top 17 is suitablysecured to the upper edges of the sides 11 and 12 and back 17 and isaccommodated by the front panel.

The bottom 13 is adapted to support a drum assembly 18 which includes acup-shaped drum 19 attached to a support and drive member 21. The drumincludes a concave tape receiving groove 22 seen in more detail in FIG.3. The drum includes a pair of slots 23 and 24 adapted to receivemagnetic transducer assemblies or heads 26 and 27 and permitslongitudinal movement of the heads.

The drive member 21 has an upper surface 25, FIG. 3, to which the drivedrum 19 is suitably secured as, for example, by screws 28. The memberincludes sides 29 and 30 forming a U-shaped housing. The side 29 carriesa plurality of spaced permanent magnets 31 which cooperate with armaturemembers 32 whereby when the armature member is electrically energized,it causes the support and drive member 21 to rotate at a predeterminedrotational velocity to, in turn, rotate the drum 19.

The complete drum and support assembly is carried by spaced bearings 34and 36 with the outer race of the bearings suitably secured to the side30 and the inner race carried by cylindrical support member 37 which issuitably attached to the bottom wall 13 whereby to support the assemblyand permit rotation of the drum and support.

A linear drive motor 41 is secured to a plate 40, in turn, secured tothe cylindrical member 37 by screws 42. The linear motor 41 has itsactuator 43 extending upwardly and engaging the magnetic transducer orhead drive and guide assembly. Referring to FIG. 6, the actuator shaft43 is shown secured to a transformer and bearing support sleeve 44 bymeans of a screw 46. Stationary rotary transformer cores 47 withwindings 48 are carried by the lower portion of the sleeve 44 and heldby the lip 49. The upper portion of the sleeve is adapted to receive theinner race of the bearings 51 and 52. The outer race of the bearingsreceives the cylindrical head driving and mounting sleeve 53 whichsupports the rotating transformer cores 54 and windings 55 of the rotarytransformer whereby digital signals may be applied to and received fromthe rotating heads.

Referring now more particularly to FIGS. 2 and 3, the head assemblies 26and 27 are supported by arms 56 and 57 secured to and extendingoutwardly from the sleeve 53. The arm supports are connected to I-beams61 and 62. The outer end of the I-beams are suitably secured to mountingplates 63 and 64, respectively. Spaced leaf springs 66 are attached tothe ends of the plate 63, extend past and straddle the I-beam 61 and aresecured to opposite sides of a mounting plate 67 supported by a mountingmember 68 suitably attached to the bottom of the drum 19 as, forexample, by screws 69. A similar arrangement is connected to the otherarm and includes parallel springs 71 having one end secured to the plate64, extending outwardly to straddle the I-beam 62 secured to a plate 72,in turn supported at their other end by support 73 suitably attached tothe drum by screws 74. This arrangement forms a parallelogram whichpermits the arms 56 and 57 to move vertically up and down but whichprevents any lateral or other movement to accurately and precisely guidethe heads 26 and 27 in longitudinal travel in the slots 23 and 24. Thisassures no tilting of the head assembly and assures that the heads cantrack closely spaced tracks formed in the record blocks.

Referring particularly to FIGS. 7-10, one of the heads 27 is shownextending through the drum 24 past the outer surface of the groove tocooperate with a magnetic tape 76. The arrows in FIG. 8 show themovement of the head in a longitudinal direction along the surface ofthe drum movement of the tape on the periphery of the drum in the grooveand the rotating movement of the drum. As will be presently described,the tape is held stationary on the surface of the drum as the drumrotates at high velocity thereby providing an air bearing for supportingthe tape adjacent the rotating head. As is known the tape will be spacedfrom the drum because of the air bearing. Even with the head extendingbeyond the surface of the groove 22 it does not move closely adjacentthe tape. For example, in a typical drum with one pound of tension foreach inch width of tape the air gap between the drum and tape may be inthe order of 0.001 inches, arrows 77 of FIG. 9. The air gap from thehead surface may be about 0.0002 inches, arrows 78 of FIG. 9. However,for high density or high frequency recording this air gap is excessive.In accordance with the present invention, air vent means are provided tominimize the air gap. One such vent comprises the space between the head27 and drum 19, arrows 78 of FIG. 9. This is about 0.004 inches toprovide some venting and maintain the tape close to the head. Inaddition, we have discovered that if grooves or notches 81 are formed inthe head, FIGS. 8 and 10, venting is provided and the tape cups ordeflects down toward the head in area of the transducer 82, FIG. 10.This provides an air gap in the order of 0.00004 inches or less. As thehead rotates, it records the longitudinal tracks on the tape and as theheads move in a longitudinal direction, records adjacent tracks witheach passage of a head over the tape.

As just described, the recording apparatus of the present inventionserves to record a plurality of recording blocks or pages along amagnetic tape with each of the blocks including a plurality of parallelrecord tracks. The recorded blocks are formed by presenting apredetermined length of tape to the surface of the rotating drum,holding the tape onto the surface with predetermined pressure wherebythe drum rapidly rotates and forms an air support between the surface ofthe drum and the overlying tape and the magnetic heads which protrudefrom the surface of the drum serve to record longitudinal tracks as theyengage and cooperate with the tape and rotate through 180° in thepresent instance. Thus, for example, head 26 records a longitudinaltrack followed by the recording of a longitudinal track be head 27 whichmay be slightly displaced from the head 26 whereby two adjacent tracksare recorded. Thereafter, the head assembly is moved by the linear drivemotor 41 to record another pair of tracks. Thus, the rotating andlongitudinal movement of the heads serves to record or reproduce aplurality of tracks from a block of magnetic tape. Thereafter, the tapeis advanced a predetermined distance whereby to record a second block.The second block is preferably spaced from the first whereby as one goesalong the tape a plurality of identifiable blocks are formed. Suitablesignals are recorded on the tracks so that they may be identified withina block. The blocks may be identified by a prerecorded track which isread with a magnetic transducer or by holes formed in the tape or byoptical markings which are sensed by photoelectric means to thereby aidin identifying and positioning each block onto the drum. Other meanssuch as magnetic means may be employed for indexing the tape. In anyevent, means are associated with the tape for moving the tape from asupply reel, placing the tape on a take-up reel and vice versa, wherebythe tape can be moved in either longitudinal direction over the drum toindex a particular selected block.

In accordance with one feature of the present invention, the tape is asingle reel disposed in a box-like housing, that is, the housingcontains only the supply reel. Means are provided for engaging the endof the tape in the supply reel, guiding it over the surface of therotating drum, and winding it onto a permanently mounted take-up reel.

Referring now particularly to FIGS. 2, 4 and 5, the tape drive portionof the apparatus is described and explained in more detail. The tapehousing 83 accommodates a reel 84. In FIG. 4 the housing is shown incooperative relationship with a drive spindle 85 secured to the shaft 86of drive motor 87. Drive motor 87 may, for example, be a stepping motorand serves to rotate the reel 84 to wind tape from the take-up reel ontothe supply reel. The tape housing 83 is placed in a U-shaped tray 88which is provided with a key 89 which cooperates with a keyway 90 in thereel housing to permit longitudinal sliding movement of the reel in andout of the tray but which retains the reel on the tray bottom 91. Thereel support tray is urged upwardly by a spring 92 secured to plate 93,FIG. 5. The housing for the tape cartridge is provided with a door orlatch 94 which may be lifted into the position shown in dotted line andurged inwardly whereby a U-shaped member 98 having surface 99 movesforward allowing the cam surfaces 101 of the tray to move upwardly underurging of the spring 92 and lift the tray upwardly to disenage the tapereel from the drive spindle whereby the reel housing may be removed anda new reel inserted in the apparatus. Thereafter, the handle 94 is drawnoutwardly to cam the tray downwardly against the force of the spring andclosed as shown in solid line in FIG. 5.

In accordance with one feature of the invention, the end of the tape isprovided with spaced pins 100 to prevent the tape from being fully woundinto the housing and which are located at one corner edge of thecartridge. When the tray is moved downwardly, the pins are adapted toengage the ends of a tape leader 102 which has its other end attached tothe take-up reel whereby as the take-up reel is rotated, the tape isdrawn from the housing into cooperative relationship with the rotatingdrum and wound onto the take-up reel. The leader 102 is shown in dottedline in FIG. 2 extending from the take-up reel to the supply reel. Theleader is guided between the reels and out of contact with the drum bymeans of two spaced ring-shaped member 106 and 107 but which are securedto spaced walls 108 and 109. The spaced members serve to guide the tapeinto cooperation with the drum after the wider leader is retracted andwound onto the take-up reel. This arrangement prevents contact of thetake-up leader with the drum surface thereby assuring no damage to theconcave tape receiving surface of the drum 19. When the tray is liftedafter all of the tape is rewound thereon, the leader 102 is, of course,adjacent the cartridge. As the tray is lifted upwardly, a pair of spacedpins 111 engage and hold the leader. Thus, after a new cartridge isinserted and moved downwardly, the retaining pins 11 are retracted whilea new set of pins from the new tape engage the end of the leader in amanner just described.

The take-up reel is driven by a motor 116 having upwardly extendingshaft 117. The shaft 117 is slotted at its ends and serves to receive apair of linear spring members 118 and 119. Ends of the spring membersare connected to the upwardly extending sides 121 of cup-shaped member122. The cup-shaped member has a downwardly extending cylindricalportion which forms the take-up reel for the assembly. Therefore, as themotor 116 is energized to rotate shaft 117, the springs flex and rotatethe take-up reel 123. Spaced guides 124 and 126 support the tape as itis reeled or wound onto the take-up hub.

As previously described, the motors 86 and 116 are energized to bringpredetermined blocks of the tape adjacent the recording drum 19.Referring to FIG. 11, a block diagram of a suitable tape control systemis shown. The rotating magnetic heads (optical readers) read the blockidentification from the tape and apply the information to a processor126 which applies signals to the motor drives 127 and 128 to bring theselected block or page into cooperation with the drum. In order toachieve consistent spacing between the heads and tape the tape tensionis controlled. The tension control is achieved by rotating the take-upreel a predetermined angular amount after the tape is located. However,depending on the diameter of the tape on the take-up reel a predetermindangular rotation will provide different tension. In accordance with afeature of the present invention the amount of rotation, steps of thestepping motor is controlled.

A step counter 129 maintains a count of the number of steps the take-upreel has taken to wind tape thereon. Of course, the count increases ordecreases depending upon the direction of rotation. This count is fed tothe processor which contains a look-up table whereby to provide anindication of tape movement (tension) in each step.

The take-up reel is provided with equally spaced markings 131, FIG. 1,which are read by an optical transducer 132. The output of thistransducer is fed to a difference counter 133 which receives a steppingsignal. The difference signal is also applied to the processor 126 whichthen provides the proper number of pulses to the stepping motor toachieve the desired constant tension regardless of block location alongthe tape.

Thus, there has been provided an improved magnetic tape drive apparatuswhich permits the use of single reels in digital recording, whichprovides high recording density, large data storage capability becauseof the multiple blocks on the tape. In essence, each block will carrysubstantial information and with tape of suitable width will carry asmuch information as a floppy disc.

What is claimed is:
 1. A magnetic tape apparatus comprising a drum,means for supporting and rotating said drum, at least one transducermounted to rotate with said drum and extending past the surface of saiddrum through a slot formed in said drum, means comprising a take-upmeans for presenting a selected length of tape to said drum so that thetransducer scans along longitudinal tracks as it rotates past said tape,means for moving said transducer longitudinally along said slot so thatit moves along a plurality of laterally spaced tracks formed along saidtape, said means including a leafspring assembly including a pair ofleafsprings with their major surfaces disposed perpendicular to thedirection of travel of said head whereby said springs can flex to permitmovement of the head along said slot but are rigid to prevent lateralmovement of the head.
 2. Magnetic tape apparatus as in claim 1 includingmeans providing a predetermined tension to said tape.
 3. Magnetic tapeapparatus as in claim 2 wherein said means for presenting selectedlengths of tape to said drum include a supply reel and take-up means formoving tape between the supply reel and the take-up means over said drumand said means for providing predetermined tension includes means formoving the take-up means after said selected length of tape has beenpresented to the drum an amount dependent upon the position of saidselected length on the tape.
 4. Magnetic tape apparatus as in claim 3wherein said take-up means includes a take-up reel driven via a torsionspring means by a stepping motor, and said means for moving the take-upmeans after said selected length of tape is presented includes means forstepping said motor an amount which is related to the amount of tape onsaid take-up reel.
 5. A magnetic tape apparatus as in claim 4 whereinsaid last named means includes means for sensing the amount of rotationof the take up reel responsive to each step of the stepping motor.
 6. Amagnetic tape apparatus as in claim 5 including means for venting saidair cushion adjacent said transducer to permit the tape to be positionedcloser to said transducer and vent means on the face of said transducerto allow a portion of said tape to extend close to the transducer. 7.Magnetic tape apparatus as in claim 1 including a rotary transformer forsupplying and receiving transducer signals.
 8. Magnetic tape apparatusas in claim 7 wherein said rotary transformer includes a stationary coreportion including a winding and a rotating core portion including awinding magnetically coupled to one another.